The subject invention relates to core making machines in general and most particularly to shell type core molding machines. However, it must be emphasized that the subject invention may be employed in connection with any type of operation, whether involved in core making, or not, wherein plugs are used to temporarily fill a jet opening or similar port aand there is a corresponding need to insert and remove the plugs at frequent intervals under safe conditions. Thus, while the principles enunciated herein are applicable mainly to a wide variety of operations, the description of the invention herein will be directed to core molding machines.
The invention herein is adapted mainly in view of the above discussion, to shell type core molding machines, in addition to other types of metal casting machines. Again, it must be emphasized that while the background discussion is directed mostly to shell type molding machines, other types of molding machines may see utilization of this invention.
In general, shell type core molding machines are used for the production of molds of variable size and exacting precision. Most such shell type core molding machines are constructed in the form of an upright apparatus, with vertically disposed, rectangularly shaped heating plates having gas or electrical heating means, functioning to provide accurate and uniform heating and curing of the core member in the casting process. In most installations the heating plate is disposed at or near the rear part of the machine just posterior of the core member. While certain other types of machines have two heating plates juxtaposed just anterior and posterior of the core member, this serves to provide uniform heating of the core. p The heating plate is comprised, in turn, of a plurality of uniformly spaced jets through which ignited gas is projected outwardly, in the form of direct flames onto the core in a direction so as to heat the core to help the curing operation. Usually such flames are projected in a horizontal direction towards or on the core.
In many situations, the number of such jets disposed in the heating plate exceed the number necessary for projecting the required amount of heat onto the core for facilitating molding and curing evolutions. Alternately stated, the heating plate generally contains more flame projecting jets than are usually necessary for the purpose of heating and curing the core in the casting process. What often occurs under such circumstances is that during many specific types of molding operations more heat in the form of combustible gases is projected out over the core than is needed for the particular operation, and consequently excess heat is wasted in the process, causing thereby loss of efficiency in the process. Such a loss of heat efficiency translates into a significant measure of lost dollars in a given manufacturing operation. As an obvious corollary, any measures that can be taken to save such an excess loss of heat helps the efficiency of operation commensurately. Various methods have been utilized in the past to alleviate such excess expenditures in metal such operations.
One such method utilized is to plug a limited number of the jets' ports, usually in alternate sequence. This leaves the remaining jets to project the desired flames, thus proportionately cutting down the amount of heat drawn and projected in the form of flames on the core. It must be noted in this regard that there is no rigid methodology for plugging the jet ports, and thus it is usually an arbitrary determination as to what arrangement is utilized to select the ones to be plugged. This determination is usually a direct function of the amount of heat desired to be directed onto the core.
The method of plugging the jet ports may vary with the circumstances, but there has not been to date a manner or device employed efficiently and effectively plugging the jet ports with devices easily and readily removed with relative facility. The subject invention is conceived to alleviate these problems and provide methodology for a rapid change of plugging jet ports as each new operation dictates; and the following objects of the subject invention are directed accordingly.